Planned, Repeat C-section May Be Safer Than Natural Birth

March 15, 2012

Delivering a second baby by Caesarean after a previous C-section may be somewhat safer for both mother and baby than a vaginal birth, according to two studies published this week in the journal PLoS Medicine.

Australian researchers found that, among babies born by a planned repeat C-section, 0.9 percent died or suffered serious complications, compared with 2.4 percent of babies delivered by a planned vaginal birth after a previous C-section.

Meanwhile, a British study found the chance of uterine rupture was decreased when mothers had an elective repeat C-section.

Women who have had a C-section often face a dilemma in their next pregnancy about whether to choose a natural birth or to have a repeat C-section. However, experts stress that the overall risks are still low for both methods.

The two current studies followed the health outcomes of pregnant women and their babies after a previous C-section.

The British study is the first to compile national data about the risk of womb rupture – a serious complication that can cause severe blood loss in the mother and put the baby at risk.

The researchers from the National Perinatal Epidemiology Unit at Oxford University identified 159 cases of womb rupture between April 2009 and April 2010, with 139 cases having occurred in women who had already undergone a Caesarean.

In women who had a previous C-section, the risk of the womb rupturing during labor was seven times greater if they tried for a natural labor than with a planned C-section, while the risk of the baby dying was three times as high.

However, the overall risk was low – 2 in 10,000 of every British pregnancies.

“This does give a true idea of the risk [of womb rupture] for the first time [in Britain] – in fact it’s lower than what we’ve been estimating before,” said Dr. Marian Knight of the National Perinatal Epidemiology Unit during an interview with BBC News.

“The important thing to remember is the absolute risks – seven times a small risk is still a small risk.”

A second study followed more than 2,000 pregnant women planning their second delivery after a previous Caesarean section at 14 hospitals in Australia.

The experts estimated that one baby death – or near death – would be prevented for every 66 planned repeat C-sections.

“Among women with one prior Caesarean, planned elective repeat Caesarean compared with planned vaginal birth after Caesarean was associated with a lower risk of fetal and infant death or serious infant outcome,” the Australian researchers concluded.

“Choosing a vaginal birth or a Caesarean section carries different risks and benefits but overall either choice is safe with only very small risks,” said Dr. Virginia Beckett, spokesperson for Britain´s Royal College of Obstetricians and Gynecologists, in an interview with BBC News.

“It is important that women discuss all the options for their individual case with their midwife or obstetrician,” said Beckett, who was not involved in the current study.

“Despite there being a slightly higher risk of rupture following a previous Caesarean, the procedure itself carries risks such as risk of blood clots, longer recovery period and the potential need for elective Caesarean in future pregnancies.”

Sue Macdonald, education and research manager at the Royal College of Midwives, said the two studies should help pregnant women and their doctors make better decisions.

“The information from the study will add to the evidence base and knowledge for midwives and obstetricians and allow them to be able to discuss with women their options for birth after a Caesarean section and whether a normal birth would be possible.”

The rate of cesarean deliveries reached an all-time high in the United States in 2009, at roughly one in three births, according to data from the National Center for Health Statistics.

The two studies were published this week in the journal PLoS Medicine. The full reports can be viewed here and here.